One of the most complex and compelling issues confronting policymakers, parents, and professionals involved in making custody decisions is this: What type of parenting plan is most beneficial for the children after their parents separate ?

More specifically, are the outcomes any better or worse for children who live with each parent at least 35% of the time compared to children who live primarily with their mother and spend less than 35% of the time living with their father ?

This article addresses this question by summarizing the 40 studies that have compared children in these two types of families during the past 25 years. Overall the children in shared parenting families had better outcomes on measures of emotional, behavioral, and psychological well-being, as well as better physical health and better relationships with their fathers and their mothers, benefits that remained even when there were high levels of conflict between their parents.

Shared physical custody, more commonly referred to as shared parenting or shared care, is the parenting arrangement in which children live nearly equally with each parent after their separation. As fathers have become more heavily involved in their children’s lives and as more mothers have resumed working full-time in the children’s preschool years, shared parenting has become more common worldwide. The majority of children still live with their mother and spend no more than every other weekend and perhaps a midweek evening visit with their father. But a change is clearly underway.

In Wisconsin, one-third of the parents who divorced in 2007 had a 50–50 shared parenting plan and one-fourth had a 25% time share (Bartfeld, 2011). Likewise, in 2008 in Washington State almost half of the children were living at least 35% with each parent in 4,354 parenting plans (George, 2008).

In Arizona, half of the parents who filed for divorce in 2002 shared the residential parenting time 20% to 32% and another 15% shared 33% to 50% of the time (Venohr & Kaunelis, 2008). It is especially noteworthy that in Wisconsin there are nearly as many infants and toddlers (42%) as there are 6- to 10-year-olds (46%) in shared parenting families for those couples who have separated in recent years (Bartfeld, 2011).

In other countries a similar trend has emerged. Rates of shared parenting have tripled in Belgium since 1990 from 9% to more than 30% (Sodermans, Vanassche, & Matthijs, 2013), have risen in Denmark and in the Netherlands to 20% (Spruijt & Duindam, 2010), and have increased to nearly 50% for parents who have recently separated in Sweden (Swedish Government, 2011).

The question, therefore, is not whether shared parenting families are on the rise. Clearly they are. The question is this: Are the children in these families any better or worse off than children living primarily with their mother and living less than 35% of the time with their father? Put more bluntly, is the inconvenience of living in two homes worth it? Fortunately, there are now 40 studies that have addressed this question. Throughout this article, the term shared parenting is used to refer to families where the children live with each parent at least 35% of the time and generally 50% of the time.

The term sole residence is used to refer to children who continue to see their fathers, but who live primarily or exclusively with their mothers. In the sole residence families, the exact amount of time that the children spent with their fathers was not designated. As noted in Table 1 (below), in 24 of the 40 studies, all of the shared parenting children lived 50% of the time with each parent. In the other 12 studies, the children lived with their fathers anywhere from 35% to 50% of the time. (NB. Table 1 is displayed here in 2 parts due to its size).

LIMITATIONS OF THE RESEARCH

Trying to determine what impact shared parenting has on children has been difficult for at least two reasons. First, children whose parents have higher incomes or have the least conflict might have the better outcomes after their parents separate, regardless of the parenting plan. So unless the study controls for income and level of conflict, this leaves open the possibility that it was not the shared parenting per se that made the difference. Unfortunately, only 16 of the 40 studies have included these controls, as noted in Table 1.

Still, even in those studies where income and conflict were not considered, it would be a mistake to presume that those two factors mattered more than the shared parenting because a number of studies have found no differences in income or conflict between sharing and non-sharing couples (Buchanan & Maccoby, 1996; Cashmore & Parkinson, 2010; Kline, Tschann, Johnston, & Wallerstein, 1989; Sodermans, Matthijs, & Spicewood, 2013).

A second limitation is that the parents’ characteristics and marital status are not the same in all the studies – and those differences can affect the outcomes for children independent of the parenting plan. For example, the majority of parents in some studies were not married or living together when their children were born—a situation that often goes hand in hand with higher rates of poverty, incarceration, physical abuse, and substance abuse.

Along the same lines, some studies draw their conclusions from extremely small, non-random samples, whereas others have impressively large, random samples. As each study is presented, the unique characteristics of the sample and the samples sizes are noted.

A third limitation is that although most of the researchers used standardized instruments and valid procedures, others used measures that had no established validity or reliability. Sample sizes also varied greatly. Describing the methodological details and naming the many standardized tests used in each of the 40 studies is beyond the scope of this article. However, the limitations of each study and whether the data came from standardized measures will be briefly noted as a way of acknowledging that the findings from some studies merit more weight than others.

METHOD

The 40 studies were identified by searching the databases in PsycINFO and Social Science Research Index. The keywords used in the search were shared parenting, shared care, joint or shared physical custody, shared or dual residence, and parenting plans. Although 85% of the studies were published in peer-reviewed academic journals, the remainder were reported in government-sponsored reports. The findings of the studies were grouped into five broad categories of child well-being as presented in Table 1:

academic or cognitive outcomes, which includes school grades and scores on tests of cognitive development such as language skills;

emotional or psychological outcomes, which includes feeling depressed, anxious, or dissatisfied with their lives; (c) behavioral problems, which include aggression or delinquency, difficult or unmanageable behavior at home or school, hyperactivity, and drug or alcohol use;

physical health and smoking, which also includes stress-related illnesses such as stomach aches and sleep disturbances; and

quality of father–child relationships, which includes how well they communicate and how close they feel to one another.

Positive Outcomes for Children in Shared Parenting Families

We begin by summarizing the positive outcomes in the shared parenting families. Twelve of the 40 studies included children under the age of 6, but only 3 of those 12 focused exclusively on children under the age of 5, which is why they are summarized separately.

U.S.STUDIES

Beginning with the oldest studies, the Stanford Custody Project collected data from 1,100 divorced families with 1,406 children randomly chosen from the county’s divorce records. At the end of 4 years, the 51 adolescents in

the shared parenting families made better grades, were less depressed, and were more well-adjusted behaviorally than the 355 adolescents who lived primarily with their mother. The data came from interviews with the adolescents, parents’ questionnaires, and a battery of standardized tests measuring depression, anxiety, substance use, antisocial behavior, truancy, cheating, and delinquency.

The shared parenting children were better off on these measures than the other children of divorce. The quality of the parent – child relationship and how often they felt caught between their parents was also assessed through interviews. The shared adolescents were less likely to be stressed by feeling the need to take care of their mother.

Moreover, having closer relationships with both parents seemed to offset the negative impact of the parents’ conflicts in those families where the conflict remained high. Importantly, this study controlled for parents’ educations, incomes, and levels of conflict; used standardized measures to assess the children’s well-being;

used a randomized sample; followed the children over a 4-year period; and gathered data from both parents and the children (Buchanan & Maccoby, 1996; Maccoby & Mnookin, 1992).

Five smaller studiesconducted in the late 1980s and early 1990s also found equal or better outcomes for the shared children. The first study included 35 shared parenting and 58 sole residence children ages 3 to 11 with White, college-educated parents (Kline et al., 1989). Standardized tests were used to measure the parents’ anxiety and depression and the children’s social, emotional, and behavioral problems, in addition to clinicians’ observations of parent–child interactions.

Although there were no differences in the children’s social or behavioral adjustment scores, the shared children were better adjusted emotionally. Having a depressed mother, having parents in high conflict (which was similar in both types of families), or the child’s having a difficult temperament was more closely linked to the children’s well-being than was the parenting plan. In another study of similar size, 3 years after the divorce, the 62 shared parenting children were less depressed, less stressed, and less agitated than the 459 children in sole residence based on standardized tests completed by the mother about the child’s mental state and behavior.

Especially important is that all of the children had similar scores 3 years earlier when their parents divorced, suggesting that the shared parenting was indeed having a positive impact (Pearson & Thoennes, 1991). The other study by these same researchers should be viewed more speculatively because there were only 9 children in shared parenting families compared to 83 children living with their mothers.

Using a standardized child behavior checklist, the two groups of mothers reported no differences in their children’s depression, aggression, delinquency, or somatic complaints (Pearson & Thoennes, 1991). In another very small study with only 11 shared parenting families and 16 sole mother and 16 sole father families 4 years after divorce, the parents reported no differences in how well-adjusted the children were on standardized measures of their wellbeing and based on researchers’ interviews with the parents and the children (Luepnitz, 1991). In yet another study with small samples, high-conflict parents who had volunteered for free counseling to resolve their co-parenting issues reported, at the end of 1 year, the 13 shared children were better off in regard to stress, anxiety, behavioral problems, and adjustment than the 26 sole residence children.

Notably, the children whose parents needed the most intensive counseling at the outset to make the shared parenting work ended up faring as well as the children whose parents initially got along best. The data were derived from clinicians’ assessments of the children on standardized measures, interviews with both parents, and feedback from teachers and day care workers at the time of separation, then again at 6 months and 1 year. It is worth noting that the shared parenting children ranged in age from 1 to 10 and that in both types of families children under the age of 4 were better adjusted than the older children (Brotsky, Steinman, & Zemmelman, 1991).

In a larger study in Toronto that was based on the researchers’ non-standardized 114-item questionnaire, only one-third of the 201 parents in shared parenting families said their parenting plan worked out well from the outset. Despite this, at the end of 1 year, 91% of these parents said their children were happy and well-adjusted, compared to only 80% of the 194 couples without shared parenting plans (Irving & Benjamin, 1991).

Overall then, even though the sample sizes were small in these studies, the findings were consistent with the larger studies in regard to the benefits of shared parenting.

More recent studies with far larger samples that gathered data from both parents have reached similar conclusions. In a large, randomized sample in Wisconsin, the children in the 590 shared parenting families were less depressed, had fewer health problems and stress-related illnesses, and were more satisfied with their living arrangement than the children in the 590 sole residence families (Melli & Brown, 2008). The data came from both parents’ answers to a series of questions asked in telephone interviews. Ranging in age from 1 to 16, the shared parenting children were 30% less likely to have been left with babysitters or in day care. Nearly 90% of their fathers attended school events, compared to only 60% of the other fathers.

Almost 60% of the mothers said the fathers were very involved in making everyday decisions about their children’s lives. In fact 13% of the mothers wished the fathers were less involved. In a smaller study with 10- to 16-year-olds, the 207 shared children were more likely than the 272 in sole residence to have parents with authoritative parenting styles, which was linked to less anxiety and less depression as measured by standardized tests (Campana, Henderson, & Stolberg, 2008). In a very small study with 6- to 10-year-olds, the 20 children in shared parenting were no less aggressive and had no fewer behavioral problems according to the standardized tests than the 39 children in sole residence after controlling for parental conflict and the quality of the mother-child relationship. Because the mothers of the shared children said they had more physical and verbal conflict with the fathers than the sole residence mothers, this suggests that whatever benefits might have accrued from the shared parenting were erased by the higher conflict (Lee, 2002).

Studies with college-age children have also found better outcomes for those from shared parenting families. In the oldest study, the 30 U.S. college students from the shared parenting families reported having better relationships with both parents than the 201 who had lived with their mothers. In fact, they rated their relationships with their fathers higher than the students from intact families (Fabricius, 2003). Similarly, 105 Canadian students from shared parenting families gave their mothers higher ratings than the 102 students from intact families and rated their fathers almost as highly (Frank, 2007). In an even larger study, the 340 shared parenting students reported having closer relationships with their fathers than the 686 who had lived with their mothers. What was especially important was that the quality of their relationships was linked incrementally to how much overnight time (‘sleepovers’), the fathers and children had spent together.

That is, as the actual amount of overnight time (aka ‘sleepovers’), they spent together during adolescence increased from 1% up to 50%, the young adults’ positive ratings of their relationships with their fathers also increased. Even the worst relationships got higher ratings when the father and child had spent more time together during the teenage years (Fabricius, Sokol, Diaz, & Braver, 2012).

Similarly in a very small study, the 5 college students from shared parenting families reported better relationships with their fathers and felt that their parents were equal in terms of their authority compared to the other 22 students with divorced parents (Janning, Laney, & Collins, 2010). And, as was true in the studies with younger children,

75 young adults from shared parenting homes reported having fewer health problems and fewer stress-related illnesses than the other 140 students with divorced parents (Fabricius & Luecken, 2007). The young adults’ ratings of their relationships with their parents in all of these studies came from questionnaires created by the researchers.

INTERNATIONAL STUDIES

Studies from other countries have yielded similar results to those in the United Statesand Canada. The one British study (Smart, 2001) only had 21 children in shared parenting to compare to the 96 children living with their mothers, with children ranging from age 6 to 16. The study is methodologically weak because the researchers merely summarized their unstructured interviews with the children. Some children adapted well and appreciated

the benefits of living equally with both parents. Others felt stressed living in two homes, especially if the parents remarried, step-siblings lived with them, or the children had trouble keeping track of their things and schedules.

A fuller picture emerges from six studies that were conducted in Sweden, using national data from standardized tests and national surveys of drug and alcohol use. In the first study, 443 shared parenting children had more close friends and fewer problems making friends than the 2,920 children in sole residence, and were no different in regard to being aggressive or violent, using drugs, and drinking (Jablonska & Lindberg, 2007).

In the second, the 17,350 shared adolescents rated themselves higher on 7 of the 11 scales of well-being than the 34,452 in sole residence (Bergstrom et al., 2013). The shared children were better off in regard to their emotional, social, and psychological well-being, peer relationships and social acceptance, and physical health. Interestingly, too, the 15-year-olds were even more similar than the 12-year-olds to the 112,778 children living in intact families, suggesting either that the benefits might become more pronounced after several years or that older teenagers benefit even more than preteens.

More important still, the shared parenting teenagers felt the most comfortable talking to both of their parents. In the third study, the 270 shared adolescents fared better than the 801 in sole residence families in regard to smoking, having sex before the age of 15, getting drunk, cheating, lying, stealing, losing their tempers, fighting, bullying, and disobeying adults (Carlsund, Eriksson, Lefstedt, & Sellstrom, 2012). In the fourth study, the 888 shared children reported being more satisfied with their lives, feeling less depressed, and having fewer stress-related health problems. Importantly, after controlling for their parents’ incomes and educations, the shared children were not significantly different from the intact family children in regard to having stress-related health problems and feeling comfortable talking to their parents about things that bothered them (Carlsund et al., 2012). In the fifth study, the 225 children aged between 10- to 16-year-olds who lived equal time with each parent were less stressed than the 595 who lived primarily with one parent.

Trained interviewers administered a questionnaire to the children as well as interviewing both the parents and the children. Importantly, this study took account of parental conflict, socioeconomic status, and the quality of the parent-child relationship. Interestingly, too, regardless of family type, the amount of conflict that the parents reported was not linked to the amount of stress their children reported (Turunen, 2014).

Similar results have emerged in Norway and in the Netherlands. In the Norwegian study, although the 41 shared adolescents were no less likely to drink or use drugs than the 409 adolescents in sole residence, they were less likely to smoke, to be depressed, to engage in antisocial behavior, or to have low self-esteem. The study used standardized tests and controlled for the father’s educational level (Breivik & Olweus, 2006).

In the Netherlands, for 135 children aged 10 to 16, the shared girls were less depressed, less fearful, and less aggressive than the girls in the 250 sole residence families, as measured by standardized tests. There were no differences for the boys.

Moreover, both the boys and the girls in the sharing families reported being as close to their fathers as the children from intact families, even though the sharing parents had similar levels of conflict and the same socioeconomic status as the non-sharing parents (Spruijt & Duindam, 2010). Similarly in another study, the 405 shared adolescents rated their relationships with both parents higher than the 1,045 adolescents who lived with their mother, although they were no less likely to report feeling depressed (Vanassche, Sodermans, & Matthus, 2014). Using a standardized questionnaire with children age 4 to 16, the third study also found that the 966 shared children were better off than the 2,217 children who lived with their mother in regard to their pro-social behavior, hyperactivity, peer relationships, behavioral problems, and psychological problems. Importantly, this study controlled for parents’ incomes, levels of conflict, and how involved the father was with the children before the parents separated. Half of the positive impact was linked to the parents having higher incomes and less conflict in the sharing families and half to the shared parenting arrangement itself (Westphal & Monden, 2014).

The more positive outcomes for children in shared parenting families could be related to the possibility that their fathers might be more likely than other divorced fathers to have an authoritative parenting style—the style that has been associated with better outcomes for children in various types of families. The one shared parenting study that tested this hypothesis found this to be true. Nearly 40% of the 139 shared parenting children between the ages of 10 and 18 rated their fathers’ parenting as authoritative compared to 30% of the children in intact families and 22% of the 227 children who lived primarily with their mother. Interestingly, the shared parenting fathers were more authoritative (40%) than the fathers in married families (30%).

This might help to explain why the shared children had higher scores on a standardized test of self-esteem and reported being more satisfied with their lives than the sole residence children (Bastaits, Ponnet, & Mortelmans, 2014).

Turning to Australia, the largest study was based on data from a national 320 survey involving 1,235 children in shared care (the term used in Australia for shared parenting) and 6,435 children in primary care (Kaspiew et al., 2009).

Unlike all of the studies discussed so far, half of these parents were not married when their children were born. Notably, even though the two groups of parents were just as likely to say there had been violence between them, “children in shared care time arrangements seem to fare no worse than children in other care time arrangements where there has been a history of violence or where there is ongoing high conflict between the parents” (Kaspiew et al., 2009, p. 273). Importantly, even after accounting for parents’ levels of education and violence, the shared care children had marginally better outcomes on the behavioral and emotional measures according to their fathers, and had similar outcomes according to their mothers.

On the other hand, if the mothers were concerned about the safety of the children when they were with their fathers, they reported worse outcomes for the children in shared care. In three other Australian studies (Cashmore & Parkinson, 2010), shared care was again more advantageous based on data from standardized tests.In the first study, 84 shared care and 473 primary care children were assessed at ages 4 and 5 and then again 2 years later.

The shared care children were less hyperactive and had fewer social or academic problems than children in primary care. In the second study, the 90 shared care parents reported better outcomes for their children than the 411 primary care parents in regard to overall happiness, problems moving between homes, and the children’s relationships with their parents and their grandparents. Again though, those mothers who had concerns about their children’s safety in their father’s care reported worse outcomes for the children in shared care. In the third study, even though the 110 children in primary care and the 26 in shared care were equally satisfied with their living arrangement, more than 40% of the primary care children said they wanted more time with their father.

Smaller Australian studies confirm the findings from these larger studies. Four years after the parents separated, 42 young adolescents in a high-conflict, sometimes violent, non-random sample of shared parenting families were compared to 44 children living with their mothers. The shared care children said they felt caught in the middle of their parents’ conflicts more often—which is not surprising as the other children’s fathers had often disengaged or virtually disappeared from their lives. This might help explain why the shared children did not feel more stressed than the other children and why they had better relationships with their fathers. There were no differences in their mental health scores and the children who were hyperactive at the outset tended to remain that way over 4 years regardless of the parenting plan.

The researchers also cautioned that the findings should not be generalized because these children had far more mental health issues than the normal population (McIntosh, Smyth, Kelaher, & Wells, 2010). Another 105 adolescents living in shared care, compared to 398 living with their mother and 120 living with their father, reported having the best relationships with both parents, their step-parents, and their grandparents 2 years after their parents’ separation. They were no different on social adjustment and academic achievement. But they were much more likely than those in sole residence to confide in their fathers (80% vs. 45%) and to say they had a close relationship with him (97% vs. 65%; Lodge & Alexander, 2010).

In a smaller study with 10-year-olds, the 27 shared care children were reported by their mothers as being less hyperactive than the 40 children in primary care. The children reported being equally satisfied with either parenting plan, but the shared care parents reported being more satisfied and less stressed than the other divorced parents. The researchers suggested that being less stressed might have enabled the sharing parents to provide higher quality parenting that, in turn, helped reduce their children’s hyperactivity (Neoh & Mellor, 2010).

Only one shared parenting study has included children from different countries (Bjarnason, 2012; Bjarnason et al., 2010). These researchers analyzed data from 40 countries involving nearly 200,000 children: 148,177 in intact families, 25,578 in single-mother families, 3,125 in single-father families, 11,705 in mother–stepfather families, 1,561 in father–stepmother families, and 2,206 in shared parenting families. The data came from the World Health Organization’s national surveys of 11-, 13-, and 15-year-olds. Consistent with the studies already discussed, only 29% of the shared parenting children said it was difficult to talk to their fathers about things that really bothered them, compared to 43% of the children who lived with their single mother or with their mother and stepfather.

In fact, the children from shared families were somewhat less likely (29%) than those in intact families (31%) to have trouble talking to their fathers. What is especially important about this study is that, in all types of families, how satisfied the children felt with their lives was closely related to how well they felt they communicated with their fathers. In contrast, their satisfaction was not related to how well they believed their family was doing financially. Because the shared parenting children felt they communicated best with their fathers, they were the most satisfied with their lives, regardless of the family’s financial situation.

Unfortunately, daughters were twice as likely as sons to say it was hard to talk to their fathers about things that were worrying them, regardless of family type.

In that vein, another question is whether girls benefit any more or any less than boys do from shared parenting. Girls’ relationships with their fathers are generally more damaged by their parents’ divorce or separation than boys’ relationships (Nielsen, 2011, 2012). Given this, we might ask: Do girls benefit more than boys from living with their fathers at least 35% of the time after the parents separate? According to several studies, the answer is yes.

Although adolescent girls felt more caught in the middle of their parents’ arguments than the boys did, the girls in shared parenting felt closer to their fathers and felt less need to take care of their mothers than the girls in sole residence (Buchanan & Maccoby, 1996). This suggests that even though girls tend to get more embroiled in their parents’ problems, living with their fathers helps to offset the damage this would otherwise do to the father – daughter relationship. Likewise, unlike the boys, adolescent Dutch girls in shared parenting families were less depressed, less fearful, and less aggressive than the girls who lived with their mothers, even though they saw their fathers regularly (Spruijt & Duindam, 2010).

Even for 3- to 5-year-olds in shared parenting, the girls were better adjusted than the boys (Kline et al., 1989). Similarly, 4- to 6-year-old girls were less socially withdrawn when they spent one or two nights a week with their fathers than when they never spent overnight time in his care ((no ‘sleepovers’). For the boys, however, the overnighting made no difference (Pruett, Ebling, & Insabella, 2004). On the other hand, in a Dutch study where parent conflict was extremely high, the girls were more depressed and more dissatisfied than the boys when they lived in a shared parenting family (Vanassche et al., 2014).

This suggests that boys might find it easier than girls to remain uninvolved in their parents’ conflicts.

Overall then, children in shared parenting families had better outcomes than children in sole residence in terms of their psychological, emotional, and social well-being, as well as their physical health and stress-related illnesses. Of equal if not greater importance, they had closer, more communicative, and more enduring relationships with their fathers.

Shared Parenting for Infants, Toddlers, and Preschoolers

Only six studies have focused exclusively on infants, toddlers, and pre-schoolers who overnighted in their father’s care after the parents separated (Table 2). Even though the children in two of those studies were not actually in “shared parenting” where they overnighted 35% to 50% of the time (Pruett, Ebling, & Insabella, 2004; Solomon & George, 1999), their findings are nonetheless summarized here because they are so often discussed in the debate over parenting plans for infants and toddlers.

In the oldest study (Solomon & George, 1999) 44 infants ages 0 to 2 were only overnighting one to four times a month – often with fathers who went weeks without seeing the infant and who had never lived with the baby’s mother. When compared to the 49 infants who never overnighted, there were no differences in insecure attachment scores or in their interactions with their mothers on a challenging task in the laboratory setting. Even though the overnighting infants, unlike the non-overnighters, had more “disorganized” (cannot be classified) attachments than children in married families, the researchers attributed this to factors other than the overnighting, namely the parents’ violence and their never having lived together. Moreover, the overnighters did not have significantly more disorganized attachments than the non-overnighters.

In the second study, with 2- to 6-year-olds, the 99 overnighters were only overnighting an average of eight nights a month (Pruett, Insabella, & Gustafson, 2005). The other 33 children spent no overnight time with their fathers, but did have contact with him. Unlike the previous study, the parents were a representative sample of lower middle-class couples with average levels of conflict and no history of substance abuse or physical abuse. Most were married and living together (75%) when their children were born. All data came from standardized tests.

For the 2- to 3-year-olds, there were no significant differences between the overnighters and non-overnighters in regard to sleep problems, depression, anxiety, aggression, attentiveness, or social withdrawal.

Likewise, for the 4- to 6-year-olds, overnighting was not linked to any negative outcomes, but was associated with more positive outcomes in regard to social problems, attention problems, and thought problems (strange behaviors and ideas, hallucinations, psychotic symptoms). Unlike the 2- to 3-year-olds, there were gender differences on several outcomes for the 4- to 6-year-olds.

The girls who overnighted were less socially withdrawn than girls who did not overnight, whereas there were no differences for the boys. The girls were also less anxious than the boys when the parenting schedule was inconsistent and when several different people were taking care of them throughout the day. The researchers attributed this to the fact that girls are more socially and verbally mature than boys their age.

Importantly, this study examined the impact of having a number of different people taking care of the child throughout the day. This is important because one of the arguments against overnighting and shared parenting for infants and toddlers is that children this young will be more anxious and distressed if several different adults are taking care of them. As it turned out, the 4- to 6-year-olds with multiple caregivers had fewer social, behavioral, and attention problems, but had more anxiety and sleep problems.

Surprisingly, though, having multiple caregivers had no impact at all on the 2- to 3-year-olds. Given this, the researchers emphasized that there is no reason to be concerned about toddlers’ being taken care of by many adults in an overnighting parenting plan. On the other hand, having a consistent, unchanging schedule and having a good relationship with each parent was more closely related to children’s outcomes than whether or not they overnighted. Overall, though, overnighting had no negative impact on the 2- to 3-year-olds and had a positive impact on the 4- to 6-year-olds, especially the girls.

The third study (McIntosh et al., 2010) compared Australian children – most of whose parents had not been married—in three types of families: no overnights, occasional overnights or ‘sleepovers’ (1–3 nights monthly for infants and 1 – 9 nights for the 2- to 5- year-olds), and frequent overnights (4–15 overnights a month for infants and 10 – 15 overnights for the 2- to 5-year-olds).

For the 4- and 5-year-olds, there were no differences on any of the six measures of well-being or physical health. For the infants and toddlers, there were no differences on overall physical health, developmental problems, or reactions to strangers. The shared parenting toddlers wheezed less often and their scores on the behavioral problems test were perfectly within normal range, although higher than the less frequent overnighters’ scores. The shared parenting mothers said their babies stared at them and tried to get their attention more often, which the researchers claimed was a sign of insecurity on their three-question test, which had no reported validity or reliability. The shared parenting mothers also said their babies were more irritable than the infants who overnighted one to three times monthly.

There seems no reason to be alarmed by this finding, however, because their irritability scores were identical to those of infants from intact families and were no higher than infants who never overnighted. Similarly, although the 19 shared parenting toddlers’ scores were worse on the task persistence scale, the scale did not differentiate healthy or normal scores from unhealthy or abnormal ones. This means there is no way to determine whether the frequent overnighters had any noticeable or significant problems that would generate any concern about lack of persistence at tasks or at play.

Unlike the other studies on shared parenting, this particular study has been frequently criticized for its methodological shortcomings and its speculative interpretations of the data. Among these shortcomings were a lack of standardized measures, very small sample sizes for the occasional overnighting babies, the high numbers of parents who had never been married or lived together (60%–90%) and the practical insignificance of many of the findings. For these reasons, social scientists have concurred that this study contributes very little to our understanding of the impact of shared parenting and provides no convincing evidence that overnighting or shared parenting is bad for infants or toddlers (Cashmore & Parkinson, 2011; Lamb, 2012; Ludolph & Dale, 2012; Nielsen, 2013; Parkinson & Cashmore, 2011; Pruett, Cowan, Cowan, & Diamond, 2012; Warshak, 2012, 2014).

Given these concerns, it is troubling that this study has been frequently misrepresented or “woozled” in the media and in academic settings as evidence that ‘sleepovers’ or overnighting has a “deleterious impact” on infants and toddlers (Nielsen, 2014).

The fourth and fifth studies are distinct in that they focused exclusively on inner-city, impoverished, never married, poorly educated, minority parents with high rates of incarceration who were part of an ongoing Fragile Families study in 20 large U.S. cities (McClanahan, 2011). In the first study (Tornello et al., 2013) five standardized measures of well-being were used to compare 103 5-year-olds who had overnighted 128 to 256 nights a year when they were 3 years old to 528 5-year-olds who never overnighted and 505 who overnighted fewer than 128 nights a year. Only one difference emerged on these five measures: The 5-year-olds who had overnighted more than 128 nights displayed more positive behavior than those who had less frequently or never overnighted.

A second difference, based on the way these researchers chose to separate the 703 3-year-olds into “frequency of overnight” groups, was that 22 of the 60 3-year-olds who had overnighted anywhere from 50 to 260 times a year at age 1 and anywhere from 128 to 260 times at age 3 were rated as insecurely attached by their mothers – a larger percentage (37%) than those who never overnighted (18%), yet almost the same percentage (33%) as those who overnighted 1 to 12 times a year.

Unfortunately, attachment data were not available for 40% of the children and, as critics of the study have pointed out (Milar & Kruk, 2012), the mothers rated their children’s behavior on a modified version of the attachment test, rather than having trained observers do the rating on a validated version of the test. This raises doubts about what was actually being measured by this unusual procedure (van Ijzendoorn, Vereijken, Kranenburg, & Walraven, 2004).

More important still, the fifth study used exactly the same data as Tornello et al. (2013) and found no correlation at all between the actual number of overnights and each individual child’s attachment score (Sokol, 2014). That is, rather than assigning the children to four different groups and then comparing the entire group’s attachment scores, Sokol correlated each child’s individual score with the exact number of overnights for that child. Using this more exact way of analyzing the data, frequent overnights were not associated with attachment insecurity. Given Sokol’s findings and the questionability of the attachment procedure itself, it is troubling that the Tornello et al. study has been misrepresented as evidence that overnighting interferes with infants becoming securely attached to their mothers.

For example, the British Psychological Society reported the study under the headline “Staying Away Affects a Baby’s Attachment” (British Psychological Society, 2013) and the University of Virginia’s press release headline read “Overnights Away from Home Affect Children’s Attachments” (Samarrai, 2011).

In part because data from these three studies have been so widely misunderstood and mis-reported, a group of 111 international experts endorsed the recommendation of Warshak (2014) in his review of the literature on infant and toddler overnighting:

“Research on children’s overnights with fathers favors allowing children under four to be cared for at night by each parent rather than spending every night in the same home. We find the theoretical and practical considerations favoring overnights for most young children to be more compelling than concerns that overnights might jeopardize children’s development” (p. 59).

“There is no evidence to support postponing the introduction of regular and frequent involvement, including overnights, of both parents with their babies and toddlers” (p. 60).

“The social science evidence . . . supports the view that shared parenting should be the norm for parenting plans for children of all ages, including very young children” (p. 59).

In the most recent study, the 16 children who had overnighted from 6 to 14 nights a month when they were under the age of 4 had closer relationships with their fathers when they were young adults than the 28 who had never overnighted and the 28 who had overnighted less frequently.

Importantly, this study controlled for the parents’ levels of conflict and education (Fabricius, 2014).

Negative Outcomes for Children in Shared Parenting

Overall then, the 40 studies show that children generally fared better in families where most of them lived half of the time with each parent. This does not mean, however, that all of these children were doing as well or better than children who were living with their mother and spending varying amounts of time with their father. Under some circumstances, the outcomes were worse for the shared parenting children. What were those circumstances?

Not surprisingly, one of the factors that sometimes diminished the benefits of shared parenting was high, ongoing conflict in which the children became involved. But did intense, ongoing conflict have any worse impact on children in shared parenting families? The answer appears to be no.

On the one hand, teenagers in shared parenting families were more likely to feel caught in the middle when their parents were disagreeing. But their parents were no more likely than other divorced parents to be in conflict.

More important, the problems between their parents were not related to the quality of their relationships with either parent, and, regardless of conflict levels, the shared parenting adolescents fared better in all measures of their emotional and behavioral well-being (Buchanan & Maccoby, 1996). For college students, those whose parents had the most conflict after their divorce were not as close to their fathers, regardless of the parenting plan. Still, living with their father more than 35% of the time was linked to a closer relationship regardless of the conflict level.

These researchers also pointed out that the negative outcomes often attributed to conflict might, in fact, be the consequence of too little fathering time, because children spend less time with their fathers when the conflict level is high (Fabricius & Luecken, 2007).

Remember, too, that children whose parents had the most conflict initially in shared parenting had just as favorable outcomes 1 year later as the children whose parents initially had the least conflict in shared parenting (Brotsky et al., 1991). In sum, the benefits of shared parenting are diminished, but not erased, when conflict between the parents remains high. Put differently, shared parenting is more likely to decrease the negative impact of high, ongoing conflict than sole residence parenting plans.

Remember, too, that gender seemed to influence the impact that conflict had on the children in shared and in sole parenting families. Girls tended to feel more caught in the middle of the conflicts than the boys did, but the girls in the shared parenting families felt closer to their father and felt less need to take care of their mother (Buchanan & Maccoby, 1996). Likewise, in Belgium the adolescent girls were more depressed and less satisfied with their lives than the boys if their parents were in high conflict (Vanassche et al., 2014). For college students, conflict in married, shared, or sole parenting families hurt the girls’ relationships with their fathers more than it hurt the boys’ relationships. Again, though, the girls in shared parenting had better relationships with both parents than the girls in sole residence (Frank, 2007).

A second factor that diminished the benefits of shared parenting was having a poor relationship with their father. Adolescents who had bad relationships with their fathers were more dissatisfied and more depressed in shared parenting families (Vanassche et al., 2014).

More seriously, when the father’s relationship with the children was one where the mother had concerns about the children’s safety when they were with him, the mothers reported worse outcomes for the children in shared than in sole residence families (Cashmore & Parkinson, 2010; Kaspiew et al., 2009). On that note, a recent study examined the links between conflict, fathering time, and the quality of the father–child relationship. All of these parents had been designated as high conflict by a judge, and all were litigating over parenting time or other custody issues. The lower the conflict, the more overnight time (‘sleepovers’), the 140 adolescents spent with their father and the more highly they rated their relationship with him. However, the children only had fewer behavioral problems when they lived with their father more than seven nights a month and when they said they had a good relationship with him. When the children felt the relationship was not a good one, then living with their father more than seven nights a month was linked to more behavioral problems (Sandler, Wheeler, & Braver, 2013).

Although not a negative outcome in the sense of creating significant or long-lasting problems for the children, living in two homes was more inconvenient for adolescents than for younger children. Given their more complicated social and academic lives, this is not particularly surprising.

Nevertheless, even the adolescents reported that living in two homes was worth the trouble, namely because they maintained close relationships with both parents. These studies were based on interviews with 22 children (Campo & Fehlberg, 2012) and 105 adolescents (Lodge & Alexander, 2010) in Australia, 40 Swedish adolescents (Haugen, 2010; Singer, 2008), 21 British adolescents (Smart, Neale, & Wade, 2001), and 22 elementary age children (Luepnitz, 1991) and 80 college students in the United States (Fabricius & Hall, 2000).

CONCLUSION

While acknowledging that some studies were more methodologically sophisticated and used more valid and reliable measures than the others, the fact remains that the 40 studies reached similar conclusions.

First, shared parenting was linked to better outcomes for children of all ages across a wide range of emotional, behavioral, and physical health measures.

Second, there was not any convincing evidence that overnighting or shared parenting was linked to negative outcomes for infants or toddlers.

Third, the outcomes are not positive when there is a history of violence or when the children do not like or get along with their father.

Fourth, even though shared parenting couples tend to have somewhat higher incomes and somewhat less verbal conflict than other parents, these two factors alone do not explain the better outcomes for the children.

By acknowledging and by disseminating the findings from these 40 studies, we can help dispel many of the myths about shared parenting and promote a fuller understanding of this parenting plan option.

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REFERENCES

Bartfeld, J. (2011). Shared placement: An overview of data in Wisconsin. Madison, WI: University of Wisconsin–Madison, Institute for Research on Poverty. 680

Sokol, K. (2014, June). Short term consequences of overnight parenting time for infants: Re-analyses of the Tornello study. Paper presented at the Association of Family and Conciliatory Courts Conference, Toronto, ON, Canada.

Hi, I am working a Shared Custody research in Puerto Rico and appreciate all the leg work you and other have done. I was looking for stats on the impact on the amount of court cases, legal fees, healthcare fees, etc. after shared custody law has been passed.

I am thinking on the society impact as whole that custody laws affect.

Thankyou for sharing this ! Well done.
One small remark : maybe the references are truncated, and something
is lost. At least there should be the “Tornello et al., 2013” study.
Can you check ?
Thanks anyway

What is not considered and included in the study is called “abuse of power” and the fact that thanks to Social Security Act Title IV D, all states are paid equal matching funds for child support ordered. It is not in the “Best interest of the Court” to award joint or shared custody. The courts lie, abuse power and position to take/steal inheritance of the children and the family nestegg. End Judicial Immunity and make process more transparent.